Studies of the intermediate phases in the reaction between barium carbonate and aluminium oxide

Abstract

A study was made of the reaction of barium carbonate with aluminium oxide both in a vacuum and in systems open to the atmosphere. Only three compounds of barium, aluminium and oxygen were found, namely BaAl2O4, BaAl12O19, and Ba3Al2O6. With the reactants in the molecular ratio 1 : 1 the only solid product was BaAl2O4. With the ratios of 1 : 6 and 3 : 1 the barium carbonate reacts first with the aluminium oxide to give the intermediate compound BaAl2O4, which then reacts with the excess reactants to give BaAl12O19, or Ba3Al2O6, respectively. The reactions appear to take place as a direct interaction of the carbonate with aluminium oxide since no barium oxide was detectable at any stage. The results are discussed in terms of Tammann temperatures.